Automatic ice making machines run essentially continuously using two basic systems. These systems are the coolant recycle refrigerant system and the water/ice system.
Problems exist which can impede the operation of an ice making machine, particularly those that run automatically for extended periods of time. One such problem that occurs is the formation and build-up of various biological growths including molds, yeast, fungi, slimes, other microbiological growths, and so forth. These microbiological growths, molds, yeast, fungi, and slimes form on the water-ice system surfaces, and can impede the flow of water through the system and can cause decreased heat transfer efficiency, particularly on the evaporator plates and ice forming molds on which ice is being made. Cleaning and sanitizing the machines typically requires a down-time. Automatic cleaning units for these machines that decrease the downtime and improve efficiency have now been developed. For instance, U.S. Pat. No. 5,289,691 describes an automatic self-cleaning, self-sterilizing ice making machine having a coolant/refrigerant system, a water-ice system, a cleaning/sterilizing system and a microprocessor operated control system interconnecting the above systems. This cleaning/sterilizing system has the capability of routinely cleaning and sterilizing surfaces in contact with circulating water/ice within the water/ice system in a way to provide clean surfaces and minimize maintenance costs and manpower involved in manually cleaning and scrubbing ice making surfaces or other water contacting surfaces which have become fouled by deposits.
However, while this automatic cleaning/sterilizing system is useful for the areas that come into contact with the water/ice, i.e. the ice bin, it does not reach those areas inside the upper portion or head portion of the ice machine above the condenser/ice making unit. Cleaning this area in a typical ice machine usually requires the removal of an access panel by means of multiple screws. Cleaning the corners of the head space manually can be difficult as parts of the ice making machine required for operation such as the water pump, are located in this area further compounding the difficulty of cleaning. Furthermore, the head space is a better incubating environment for microbial growths than the ice bin itself because the temperature is higher and the humidity is high. Gaseous chlorine dioxide in low concentrations (i.e. up to 1,000 p.m.) is known for its utility and effectiveness as an antimicrobial, i.e. fungicide and bactericide, and also as a deodorant. It is particularly useful where microbes and/or organic odorant are sought to be controlled on and around foodstuffs, as chlorine dioxide functions without the formation of undesirable side products such as chloramine or chlorinated organic compounds that can be produced when elemental chlorine is utilized for the same or similar purposes. For example, if a low concentration of chlorine dioxide gas can be maintained in contact with fresh produce for several days during shipping from the farm to the local retailer, the rate of spoilage of the produce can be decreased. Additionally, chlorine dioxide gas is also generally considered as safe for human contact at concentrations effective for deodorization and for most antimicrobial applications because the required concentrations are so low.
U.S. Pat. No. 6,077,495 describes a method, composition, and system for generating chlorine dioxide gas in a controlled release manner.
U.S. Pat. No. 5,974,810 describes a method and composition for producing ice having substantially no undesirable taste and odor characteristics comprising freezing ice in the presence of chlorine dioxide gas.